An organic thin film transistor (OTFT) is a logic unit device employing an organic semiconductor for an active layer. As compared to an inorganic transistor, the OTFT has the following main advantages. (1) There are more film technologies for forming an organic thin film, such as Langmuir-Blodgett (LB) technology, molecular self-assembly technology, vacuum evaporation, ink-jet printing, and so on, and thereby the manufacturing process can be made to be simple, diversified, and at a low cost; (2) organic materials are easy to be obtained; (3) the manufacturing process of the OTFT can be more simple, does not require strict regulation on ambient conditions, and does not have a harsh requirement on purity, and thus costs of a device can be reduced effectively, and the device has characteristics of being suitable for large-area processing, flexible substrate compliance, and low costs for process. Owing to the above merits, the OTFT holds promising application prospective in the field of flat panel displays.
However, in accordance with the manufacturing process of an OTFT at present, in the course of producing a conductive thin film on an active layer and patterning the conductive thin film with a photolithography process (i.e., in the course of producing a first contact layer unit, a second contact layer unit, and source and drain electrodes), a portion in the active layer functioning as a channel may be damaged to a certain degree; the quality of the channel directly affects the quality of the OTFT, and in turn, the quality of a display panel is affected.